Megarthropoda
Megarthropoda is a clade of arthropods whose unique physiology has allowed them to grow to sizes more common among tetrapodal species. Some have developed a kind of communal sapience with cultures, only recently recognized as such by scholars due to their alien nature. They include the achamatl and the mak'ti. They are believed to have been dwelling on the lands of Torvalen even before tetrapodal life left the water. In this time they became very diverse, though they share some key features that have allowed them to gain their size and relative intelligence compared to other arthropods.
Megarthropods are covered in chitin scales or plates, which do not need to be molted in order to grow larger, unlike other arthropods. Their bodies are tri-segmented with six true legs and two sets of mandibles, which in some species have adapted to limb-like functions. They also possess chitinous endoskeletons to which muscles attach and give them the internal support to allow them to grow large. They have an hemoglobin based, closed circulatory system with three hearts, two of which pump blood for gas exchange from their highly modified book lungs. The exceptions are the Achamatl and their less intelligent relatives, who readapted to an aquatic environment and redeveloped gills. All megarthropods sensory organs include two sets of compound eyes, one set usually dominant over the other, as well as antennae.
Because of some of these key adaptations, they grew to enormous sizes before the arrival of tetrapods who, due to their lower metabolisms and more efficient gas exchange, were able to out compete them in most ecologies when global oxygen levels decreased. Those that survived were those occupying full aquatic, arboreal or underground habitats. However, a few flight capable species occupying the ancient desert of interior Kalmasa also survived, due to their enhanced respiration and safety in their dry, isolated environment.
Comments